Method for the integrated management of the parameters regarding the cutting of road surfaces and road scarifier implementing said method

ABSTRACT

The invention is a road scarifier for cutting road surfaces, comprising: a frame provided with a cutter, supported by tracks by means of hydraulic actuators suitable for modifying the position of said cutter with respect to the road surface; driving means to obtain the setting in motion of the machine and the rotation of said cutter; right and left sensors arranged at the sides of the machine and suitable for measuring the distance from the road surface; sensors to show the inclination of said machine with respect to the horizontal plane. Each one of the right and left sensors and said inclination sensor (α) sends signals to first data processing systems, the first data processing systems being suitable for comparing the values measured with those preset and for sending out difference signals that are received by a data processing unit capable of sending control signals to hydraulic actuators connected to the frame of the machine, in such a way as to reduce to zero the difference signal sent out by said first data processing systems.

BACKGROUND OF THE INVENTION

[0001] The invention concerns a method for the integrated management ofthe parameters regarding the cutting depth of road surfaces and a roadscarifier suitable for implementing said method.

[0002] It is known that road scarifiers are machines equipped with acutting drum that sinks into the road surface for a given depth, in sucha way as to remove the asphalt and prepare a bed suitable for the layingof a new asphalt blanket. Depending on the different needs, the roadscarifier must remove the road surface until reaching a given depth, forexample 10-15 cm with respect to the road level. Sometimes, besidesremoving the asphalt in horizontal direction, or in any case parallel tothe road surface, it is necessary to remove the asphalt in a differentmanner from the right to the left side of the road, for example when aroad with sloping sides for the drainage of rain must be obtained, thatis, a road whose sides are lower with respect to its centre to avoid thestagnation of water.

[0003] In this case it may happen that, if the road surface in questiondoes not have this geometrical configuration, to obtain an inclinedprofile the scarifier must cut the road deeper on one side than on theother. Practically, the cutting drum must not be parallel to the roadsurface, but inclined of an angle α with respect to the same.

[0004] In order to obtain these specific effects in the preparation ofthe road bed for the laying of a new asphalt blanket, the known roadscarifiers use copying devices, like for example tracer points thatcooperate with a wire tensioned through a series of pegs arranged on theroad side.

[0005] According to this method, the tracer point is constantly incontact with the tight wire and when this contact is lost an automaticcorrection of the machine position takes place by means of hydraulicjacks that operate on the frame, in such a way as to vary the workingdepth of the cutting drum and restore the contact between tracer pointand wire.

[0006] If it is not possible to use pegs and tight wire, the machine isequipped with a long linear bar positioned at the side of the machineitself and resting on the road surface, in such a way as to define amedian plane that is followed by the machine in operation.

[0007] Besides these devices, which substantially control the cuttingdepth, there are also devices that show the inclination of the cuttingdrum with respect to the road surface, in such a way as to removedifferent quantities of asphalt on the left and on the right side of thedrum, respectively, and to obtain a given road profile, for example withsloping sides.

[0008] More generally, road scarifiers are provided either with sensorspositioned on the left and on the right side of the machine and suitablefor measuring the distance between the sensor and the cutter contactsurface, and with devices controlling the inclination of the cuttingdrum.

[0009] At present these data are read and managed by the machineoperator in a non-coordinated way, which means that if the machine mustdrive the cutter into the road surface for a given depth—for example thesame depth on the right and left side—the operator of the machine mustprogramme the right depth control instrument and the left depth controlinstrument separately, presetting a certain working depth for the rightand left sides of the road.

[0010] According to the known technique, therefore, the right and leftscarification depth control devices cannot exchange information in orderto correct any deviation from the preset parameters.

[0011] Practically, according to the technique used at present there isno interdependence between the measured parameters regarding rightdepth, left depth and inclination, which would ensure the completecontrol of the cutting profile to be obtained.

SUMMARY OF THE INVENTION

[0012] The aim of the present invention is to overcome the limitationsof the known technique.

[0013] Another aim of the invention, in fact, is the implementation aroad scarifier for the cutting of road surfaces that constantly ensuresthat the work of the cutting drum on the road surface is performed insuch a way as to obtain the desired profile, and therefore followingpreset parameters.

[0014] Said profile should also be automatically respected by themachine, which means that during the operation of the machine automaticcorrection in response to deviations from the preset parameters shouldbe possible.

[0015] Another object of the invention is to facilitate the work for theoperator of the machine, by grouping on a single panel the controlsregarding the parameters of the scarification profile to be obtained,that is, the right depth, left depth and inclination parameters of theroad surface removed.

[0016] A further aim to be achieved is that the scarifier control systemshould make it possible to operate the machine by setting only two ofthe three parameters of the scarification profile to be obtained, whilethe third parameter should be derived from the other two.

[0017] Another aim of the invention is the implementation of a machineequipped with a device that, whenever a deviation from the presetparameters takes place, intervenes with an automatic correctionprocedure acting directly on the components that vary the position ofthe machine and of the cutting drum with respect to the road surface onwhich the work is being performed.

[0018] All the aims mentioned above and others that will be described ingreater detail below have been achieved through the implementation of aroad scarifier for cutting road surfaces, comprising:

[0019] a frame provided with at least one cutting drum, preferablysupported by tracks by means of hydraulic actuators suitable formodifying the relative position of said frame and said tracks, in such away as to modify the axis of said cutter with respect to the roadsurface;

[0020] driving means to obtain the setting in motion of the machine andthe rotation of said cutter;

[0021] right and left sensors arranged at the sides of the machine andsuitable for showing the relative distance between said sensors and theroad surface; sensors to show the inclination of said machine withrespect to the horizontal plane, said road scarifier being characterizedin that each of said right and left sensors and said inclination sensorsends signals to first programming and controlling data processingsystems, said first data processing systems being suitable for comparingthe signals received with preset signals and for emitting differencesignals that are received by a second data processing system capable ofsending control signals to hydraulic actuators connected to the frame ofthe machine, in such a way as to reduce to zero the difference signalssent out by said first data processing systems.

[0022] The object of the invention includes also the road scarifieroperation method for the removal of asphalt from road surfaces throughthe cutting of the asphalt with preset depth and inclination, comprisinga presetting cycle for the definition of the parameters to be obtainedand a working cycle according to the contents of the independent claimregarding said method.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Further characteristics and details of the invention will bebetter highlighted in the description of one favourite application amongmany of the invention in question, illustrated in the enclosed drawings,wherein:

[0024]FIG. 1 is a front view of the machine object of the invention;

[0025]FIG. 2 is a plan view of the machine object of the invention,showing in particular the position of the hydraulic jacks with which themachine is equipped;

[0026]FIG. 3 is a schematic section of the machine object of theinvention along line III-III, showing in particular the hydraulicdiagram of the front hydraulic jacks;

[0027]FIG. 4 is a schematic section of the machine object of theinvention along line IV-IV, showing in particular the hydraulic diagramof the rear hydraulic jacks and the machine inclination sensor;

[0028]FIG. 5 is a block diagram of the control devices with which themachine object of the invention is equipped;

[0029]FIG. 6 shows a section of the road surface removed by the machineobject of the invention; and

[0030]FIG. 7 shows by means of a table the possible operation modes ofthe rear actuators and of the inclination sensor of the machine objectof the invention.

[0031] With reference to the figures mentioned above, it can be observedthat the road scarifier, indicated as a whole by 1 in FIG. 1, isprovided with a frame 2 supported by tracks 3, 4, 5 and 6, on which thesame number of jacks indicated by 7, 8, 9 and 10 rest, as shown in FIG.2.

DESCRIPTION OF THE INVENTION

[0032] The road scarifier is equipped with a cutting drum 11 suitablefor working on the road surface 12 according to the position of thehydraulic jacks that lift or lower the frame 2 as required by the workprogramme.

[0033] It must be observed that road scarifiers are generally providedwith front jacks 8 and 9 operated by a single hydraulic control, so thatthey act together as if they were a single central jack positioned atthe front of the machine, as shown in the hydraulic diagram of FIG. 3.On the other hand, as far as the rear jacks 7 and 10 are concerned,these are controlled independently of each other and can have differentconfigurations, so that the cutting drum 11 can be parallel to the roadsurface, or inclined as much as necessary to obtain the scarificationaccording to a given profile, for example with sloping sides, in such away as to obtain an asphalt covering having certain specificcharacteristics.

[0034] According to the invention, the road scarifier 1 is provided onboth sides with sensors, indicated by 13 and 14, respectively, that canbe seen in FIG. 2 and 1. These sensors can be ultrasound sensors orreflection sensors and serve to measure the distance between saidsensors and the road bed.

[0035] As it can be observed in the block diagram of FIG. 5, the sensors13 and 14 send their signals to first programming and controlling dataprocessing systems indicated by 16 and 17, respectively. Moreparticularly, the sensors 13 send their signals to the data processingsystem 16 and the mean of said signals is made and shown on a display161.

[0036] Analogously, the sensors 14 send their measure signals to thedata processing system 17, which shows the mean of the readings on thedisplay 171.

[0037] As already explained, the road scarifier is also provided with aframe inclination sensor indicated by 18, which in fact shows theinclination angle α of the frame with respect to the horizontal line ofthe machine. Since the cutting drum 11 is integral with the frame 2, theinclination of the frame obviously corresponds to the inclination of thecutting drum, which is the inclination that is actually relevant to thework performed by the machine. Even in this case the inclination sensor18 is connected to a further first data processing system 19 that showsthe measured inclination, expressed in degrees, on the display 191.

[0038] According to the invention, it is possible to set two of thethree parameters necessary for the setting of the scarification in thefirst data processing systems 16, 17 or 19, since the third parametercan be derived from the other two. More particularly, it is possible toset the left and right scarification depth parameters in the dataprocessing systems 16 and 17 through the displays 162 and 172,respectively.

[0039] Obviously, if the right and left scarification depth values arethe same, the angle α on the display 192 of the data processing system19 will be equal to 0. The situation will be different if the leftscarification depth value differs from the right scarification depthvalue and in this case the value of the angle α will be derived directlyfrom the difference between the two values set.

[0040] It is clear, therefore, that to preset the operation parametersof the road scarifier it will be necessary to preset two of the firstthree data processing systems 16, 17 and 19, that is, the respectivevalues required, the third value resulting directly from the other two.

[0041] More particularly, if the two scarification depth values are set,the inclination angle value will be set as a consequence of the othertwo. It is also possible to set the value of the left or rightscarification depth together with the desired inclination angle, and theother right or left scarification depth value will be consequentlydefined and preset and then automatically displayed by the first dataprocessing systems.

[0042] When the machine is in operation, each data processing system 16,17 or 19 carries out a comparison between the scarification depth orangle set and the corresponding readings, by means of an electronicprocessor. Consequently, a difference signal δS, δD and δα is sent outby the first data processing system 16, or 17, or 19, respectively.These difference signals are received by a second data processing systemPLC, indicated as a whole by 20, which processes the signals receivedand sends control signals to hydraulic left and right actuators,indicated by 21 and 22, respectively, which control the hydrauliccylinder 10 and the hydraulic cylinder 7, respectively, so that thelifting or lowering of each one of the hydraulic cylinders tends toreduce to zero the difference signals δ received by the first dataprocessing systems 16, 17 and 19.

[0043] It is clear that in this way the road scarifier object of theinvention, with its control device, controls all the parametersregarding the scarification carried out by the cutting drum and adaptsthe position of the machine through the operation of the hydraulicjacks, in such a way as to follow the desired scarification profile.

[0044] From an operational point of view, the first step necessary tocarry out the scarification according to preset parameters as describedherein is represented by the setting of the parameters, which isfollowed by the actual scarification process.

[0045] For the parameter setting cycle, first of all it is necessary tooperate the hydraulic jacks of the machine, in such a way as to lift theframe with the maximum extension, that is, at the maximum distance ofthe same from the ground, after which the jacks must be lowered untilthe cylinder rests on the ground. With the cylinder resting on theground and parallel to the road surface to be scarified, the measuredvalues shown by the displays 162, 172 and 192 are read and then set tozero by means of the reset buttons positioned on each first dataprocessing system, indicated by 163, 173 and 193. Once the values areset to zero, the desired values are set in two of the three displays162, 172, 192 belonging to the data processing systems 16, 17 and 19,according to one of the combinations shown by the table in FIG. 7. Forexample, as it can be observed for the setting 1 of the selector 30, thevalue LS can be set in the display 162, the value LD in the display 172,and the angle α will be set in the display 192 as a consequence of theother two settings.

[0046] Another option is available, according to position 2 of theselector 30 of FIG. 7, if the operator decides to set the rightscarification depth value LB and the inclination angle α. In this casethe left scarification value LS will automatically derive from the othertwo settings.

[0047] It may also happen, as shown in line 4 and 5 of the table of FIG.7, that the left or right cylinder respectively are kept inoperative andtherefore fixed in their initial position. The position 6 indicates thatthe machine is at rest.

[0048] Therefore, once two of the three reference values have been set,as explained above, in each one of the first data processing systems 16,17, or 19, it is possible to start the work.

[0049] As soon as the scarification work is started, the sensors 13, 14and 18 transmit the scarification depth and inclination angle valuesmeasured to the respective data processing systems. These values arecompared with the set depth and inclination angle values and, if thereis a difference between the values read and those set, the first dataprocessing systems send out a difference signal δS, δD or δα. Thesesignals are received by a data processing unit, for example a PLCindicated by 20, which sends out one or two signals, 21 and 22, thatoperate the hydraulic actuators 7 and 10. Said cylinders are operated inorder to obtain a variation in the position of the frame 2, in such away as to reduce to zero the difference δS, δD or δα signalled by thefirst data processing systems 16, 17 and 19.

[0050] If the machine keeps working with constant value readings and ifthe readings substantially correspond to the preset values, nodifference signal will be sent out by the first data processing systemsand consequently the PLC 20 will not emit any signal to operate thehydraulic actuators 7 and 10.

[0051] It is clear that, according to the invention, it is possible toobtain the full automatic control of the geometrical configuration ofthe scarification profile, after presetting the starting data.

[0052] It is also obvious that thanks to this possibility of presettingthe parameters the road scarifier can obtain any scarification profile,an example of which is shown in FIG. 6.

1) Road scarifier for cutting road surfaces, comprising: a frameprovided with at least one cutter, supported by tracks by means ofhydraulic actuators suitable for modifying the relative position of saidframe and said tracks, in such a way as to modify the position of saidcutter with respect to the road surface; driving means to obtain thesetting in motion of the machine and the rotation of said cutter; rightand left sensors arranged at the sides of the machine and suitable forshowing the relative distance between said sensors and the road surface;sensors to show the inclination of said machine with respect to thehorizontal plane, wherein each of said right and left sensors and saidinclination sensor sends signals to first programming and controllingdata processing systems, said first data processing systems beingsuitable for comparing the measured values with the preset values andfor emitting difference signals that are received by a signal processingunit capable of sending control signals to hydraulic actuators connectedto the frame of the machine, in such a way as to reduce to zero thedifference signals sent out by said first data processing systems. 2)Road scarifier according to claim 1, wherein the values preset in saidfirst data processing systems are two, the third value being deriveddirectly from the other two. 3) Road scarifier according to claim 1,wherein said data processing unit is provided with a selector suitablefor enabling two of the three first data processing systems,indifferently, for the presetting of data the third of said first dataprocessing system being set consequently. 4) Road scarifier according toclaim 1, wherein the hydraulic actuators are hydraulic cylinders, moreprecisely two front and two rear cylinders, said front cylinders beinghydraulically connected to each other, so that they can be operated bymeans of a single control. 5) Method for the operation of a roadscarifier according to claim 1, suitable for removing asphalt from roadsurfaces by cutting with preset scarification depth and inclination,comprising a first cycle for the setting of the parameters to beobtained and a working cycle, wherein it comprises the following steps:A) lifting the hydraulic jacks supporting the frame of the machine andresting on the tracks with maximum extension; B) lowering the hydraulicjacks until the cutting drum of said scarifier rests on the roadsurface; C) measuring the distance between the road surface and thelateral sensors positioned on the right and left side of the machineframe, by means of a first right data processing system and of a firstleft data processing system, respectively; D) measuring the transversalinclination of the machine by means of an inclination sensor and afurther first data processing system; E) sending said signals to saidfirst right and left data processing systems and to said inclinationdata processing system on the respective first right scarificationdepth, left scarification depth and inclination display; F) setting tozero the values shown by said first displays by means of a reset buttonacting on each one of said first data processing systems; G) setting twovalues chosen among the right scarification depth, left scarificationdepth and inclination in two of said first data processing systems; andin that the working cycle comprises the following steps: A1) startingthe rotation of the cutting drum and the machine; B1) sending the valuestaken by said right and left sensors and by said inclination sensor tosaid first right and left scarification depth data processing systemsand inclination data processing system; C1) comparing the values takenwith the values preset in said first data processing systems; D1)sending out a difference signal from each first data processing system,said difference signal being proportional to the difference between thevalues taken and those preset and being received by a data processingunit; E1) sending out control signals from the data processing unit tohydraulic actuators connected to the frame of the machine, said controlsignals being such as to vary the values measured by the right and leftscarification depth sensors and by the inclination sensor, in such a wayas to restore the preset values.